Organizing Files better than using folders?

[FOBSIDE]

I work with a a lot of files and I am wondering if there is any software, preferably free, that anyone has come across that can organize files better than using just folders. I am basically trying to keep documentation for various offices organized. There is no specific type of file that is used. Sometimes it is .doc, .xls, or sometimes it is some other format. Is there a way to be able to browse and look at files in a virtual binder rather than having to enter each directory and backing up when I need to enter another folder?